IPC or UPC for California?

Rachel, the UPC/IPC standards were derived from the federal Energy Policy Act (EPAct) of 1992, so the 2007 California codes should be equivalent or better. For LEED purposes, the UPC/IPC codes have been adopted to help calculate the consumption baseline. The best thing to do would be to download a sample WEp1 credit form from LEED-Online and use the built-in calculators to help determine your LEED baseline. Custom calculations will not be accepted during your application review, so it's best to always use the materials provided by the USGBC to perform these types of calculations.